The present invention pertains to a liquid dispenser for dispensing and coating liquids such as adhesives or silicone resin liquids, etc. in tiny quantities with high precision on circuit boards when mounting electronic components, etc.
Syringes for despensing liquids in tiny quantities with high precision onto circuit boards have been previously been proposed by the present inventor and others, and one is found in Examined Utility Model Application Hei 5-9099. This art pertains to a container (i.e. syringe) filled with liquid held in an adapter having a valve stem and actuator that raises and lowers the valve stem. A valve mechanism constituted by the aforesaid valve stem and a nozzle at the tip of the syringe opens and closes, and the liquid inside the syringe is dispensed in tiny quantities with high precision.
However, containers (syringes) filled with liquid available on the market come in many different sizes. Among these, the four types most commonly encountered are 50 cc, 30 cc, 10 cc, and 5 cc. To apply the liquid dispenser disclosed in the aforesaid Examined Utility Model Application Hei 5-9099 to these syringes of different sizes one must prepare liquid dispensers fitting the various sizes due to discrepancies in the clamp mechanism holding the syringe or in the valve stem length dimension; this is very troublesome, and preparing a liquid dispenser for each syringe size is very costly, so improvement is required.
Also, in the prior-art liquid dispenser disclosed in the aforesaid Examined Utility Model Application Hei 5-9099, gas pressure for dispensing the liquid remains inside the syringe when replacing a syringe, so the clamp mechanism must be released after releasing this pressure by some means. However, it often happens that an operator forgets to release residual gas pressure inside the syringe, and if the syringe is erroneously removed while gas pressure remains inside the syringe, the syringe violently blows off due to gas pressure at the instant the clamp mechanism is released, and this is very dangerous.
In other words, the present invention considered the aforesaid problems, so its object is to provide a liquid dispenser that enables a single type of liquid dispenser to handle a variety of sizes of syringes by providing a few accessory components for a variety of syringes of different sizes. An additional object is to provide a safe-to-operate liquid dispenser that releases residual gas pressure in a syringe when replacing a syringe. An additional object is to provide a liquid dispenser whose dispensing valve has good responsiveness in opening and closing.
The present invention used the following sort of method to solve the aforesaid problems. Below, for ease of understanding, explanation shall be provided using the codes used in the working examples and to be described later. That is, the present invention is a liquid dispenser, comprising:
a. a frame formed by upper bracket and lower bracket and designed to conform to the maximum syringe size matching the use objective,
b. a body that is removable at the aforesaid frame""s upper bracket, and provided at its upper end with a threaded part for installing an actuator and provided at its lower end with an insertion part for insertion into a syringe and an installation part for an attachment,
c. an actuator installed at the threaded part provided at the upper end of the aforesaid body,
d. a valve stem operated by the aforesaid actuator, and
e. a valve seat member installed at the tip of syringe and formed to be removable at the aforesaid lower bracket.
Also, the liquid dispenser is a liquid dispenser in which the actuator consists of an actuator using electromagnetic force, and the actuator is attached to the body by a thread that includes a magnetic force regulation means.
Also, the liquid dispenser is a liquid dispenser incorporating a means for automatically releasing pressure gas in the syringe when the dispensing mechanism consisting of the body, actuator, valve stem, syringe and valve seat member is removed from the frame.
Also, the liquid dispenser is a liquid dispenser in which an attachment conforming to a different size syringe is provided and is freely removable from the body.